Evolutionary principles and the genomic basis of convergent evolution of traits and characters in the Arabideae.

一般来说，生命，特别是植物，在进化的时间尺度上适应新的环境。研究适应是必不可少的，如果我们的目标是了解生命如何在不断变化的环境中生存，这是当今世界的一个直接相关的话题。适应性的研究往往受到缺乏复制的限制，没有独立的复制，就不可能确定我们在自然界中看到的东西有多少是特定于某个例子的，有多少可以被视为一般的结果或规则。然而，趋同进化使我们能够克服这一基本限制，因为这一过程是自然界自己的复制实验，以产生一种表型。这常常导致趋同进化。趋同进化描述了同一表型在不同进化谱系中的独立发展。自达尔文时代以来，对趋同现象的观察就一直令人着迷，但人们仍然不明白，大自然如何能够为远亲物种的问题发明同样的解决方案。最直观的趋同进化是适应相似条件的结果。然而，它也可以是限制的结果，例如发育或突变。此外，基因渗入也可以被认为是收敛的来源，当研究植物中的收敛进化时，特别感兴趣的概念，其中多倍化，网状进化和杂交是常见现象。研究趋同进化需要有大量的自然复制品，也就是说，要分析的性状不同的多个姐妹谱系的类群。在菊科家族中，阿拉伯树族是最突出的族之一，它正好显示了这一必要的特征。它是一个单系组合，大约有500种分布在18个公认的属中，在所有主要谱系中发现了性状和性状复合体的趋同。在我们的项目中，我们使用比较基因组方法来寻找植物形态空间平行进化的基因组足迹，解释趋同表型和选择的复杂性状。人们经常看到，一些性格和特征是结合在一起的，甚至表现出作为一种综合征的趋同性。在这里，我们专注于一个最极端的性状，即一次结实（一年生）与多次结实（多年生）的生活史，这已经独立地在菊科进化了很多次。时空环境证据将从关于分布范围和发散时间估计的数据中间接收集。我们寻求深化我们的见解，以更好地了解一个大的植物家族的成功进化历史，以最高的速度多样化的原则。

Life in general, and plants in particular, adapt to a new environment on evolutionary time scales. Studying adaptation is essential if we aim at understanding how life persists in the face of changing environments, a topic of immediate relevance in today’s world. The study of adaptation is often limited by a lack of replication and without independent replication it is impossible to determine how much of what we see in nature is particular to a certain example and how much can be regarded as a general result or rule. However, convergent evolution allows us to overcome this fundamental limitation, as this process is nature’s own replicate experiment in generating a phenotype. This leads very often to convergent evolution. Convergent evolution describes the independent development of the same phenotype in different evolutionary lineages. The observation of convergence has fascinated humans since Darwinian times already and it is still puzzling how nature is being able to invent the same solution for a problem in distantly related species. Most intuitively convergent evolution is the result of adaptation to similar conditions. However, it can also be the result of constraint, e.g. developmental or mutational. Furthermore, introgression can also be considered as a source for convergence, a notion which is of particular interest when studying convergent evolution in plants where polyploidization, reticulate evolution and hybridization are a common phenomenon. Studying convergent evolution requires the availability of a large number of natural replicates, i.e. groups of taxa where multiple sister lineages are found that differ in the traits to be analysed. Within the Brassicaceae family the tribe Arabideae is one of the most prominent tribes and it displays exactly this required feature. It is a monophyletic assemblage with roughly 500 species distributed among 18 accepted genera where convergence of traits and trait complexes is found in all main lineages. With our project we are using comparative genomic approaches to seek for genomic footprints of parallel evolution of the plants morphospace explaining convergent phenotypes and also selected complex traits. It is often seen that some of the characters and traits are combined and show even convergence as a syndrome. Here we focus on one of the most extreme traits, namely evolution of monocarpic (annual) versus polycarpic (perennial) life history, which has evolved many times independently in Brassicaceae. Spatio-temporal environmental evidence will be collected indirectly from data on distribution ranges and divergence time estimates. We seek for deepening our insights into the principles of Brassicaeae evolution in order to understand better the successfully evolutionary history of a large plant family diversifying at highest rates.